Clary sage is cultivated mainly for the production of its essential oil, sclareol, and sclareol derivatives. U.S. Pat. No. 3,060,172 describes a process for the isolation of sclareol from clary sage. One sclareol derivative, sclareolide, has been used extensively as a major perfume component, as a wine and foodstuffs flavorant, and as a cigarette flavorant. It has therefore been of interest to develop methods of producing high-purity sclareolide in large amounts.
U.S. Pat. Nos. 5,525,728 to Schneider et al., and 5,247,100 to Gerke et al. describe processes for the production of sclareolide from sclareol. Briefly, these processes use a ruthenium catalyst and an oxidation step to convert sclareol into a crude sclareolide product. Sclareolide may be also be produced by the methods generally described in U.S. Pat. Nos. 4,970,163 and 5,212,078, both to Farbood et al. Generally, the Farbood et al. methods utilize a biotransformation (fermentation) process in which one or more microorganisms (e.g., Cryptococcus albidus, Bensigntonia ciliata) are used to convert sclareol into useful sclareolide compounds. Although the microbial transformation procedure is preferable to the chemical conversion process, the sclareolide product that is provided by biotransformation contains microbial cell debris and other fermentation by-products that render the sclareolide unsuitably impure. Accordingly, an additional purification process is required in order to provide a sclareolide product that is suitable for commercial purposes. The existing processes that are used to further purify sclareolide produced by biotransformation are inefficient in removing microbial cell debris, and generally involve a costly recrystallization step in which a significant amount of sclareolide is lost in the mother liquor.
Accordingly, it is highly desirable to provide an alternative method of purifying sclareolide that has been produced by biotransformation. Such a method would desirably eliminate cell debris and other fermentation by-products from the sclareolide product, and provide sclareolide with very high purity levels and enhanced aroma and appearance characteristics.